Decoupling the effects of crystallinity and orientation on the shear piezoelectricity of polylactic acid

Lovell, Conrad S.; Fitzgerald, James W.; Park, Cheol

doi:10.1002/polb.22345

Cited by 44 publications

(42 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After reaching 220°C, the sample was held at this temperature for 5 min before ramping down to 0°C at a ramp rate of 20°C/min. %Crystallinity of the samples were calculated using the equation

% Crystallinity = \frac{Δ H_{f}^{normalobs}}{Δ H_{f}^{\circ}} = \frac{Δ H_{m} - Δ H_{c}}{Δ H_{f}^{\circ}}

where

Δ H_{m}, Δ H_{c}

and

Δ H_{f}^{o}

(= 93.1 J/g) are enthalpy of melting, enthalpy of crystallization and enthalpy of fusion for 100% crystalline PLA, respectively.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The microstructure and mechanical properties of 3D printed carbon nanotube‐polylactic acid composites

et al. 2017

View full text Add to dashboard Cite

This article reports 3D printing of carbon nanotube‐polylactic acid (CNT‐PLA) composites using an extrusion‐based Fused Deposition Modeling (FDM) method. CNTs with an average diameter of 128 nm and an average length of 2.5 μm were first compounded with PLA and extruded into feedstock filaments at 0.5%, 2.5%, and 5% (w/w) CNT loadings. CNT aggregates were observed, but no clogging occurred during printing with a 500‐μm print nozzle. The rheology of the CNT‐PLA samples was characterized to understand the printing‐induced alignment of CNTs along the road axis. Additionally, the effect of printing flow rate was explored for a fixed printing gap and nozzle diameter. Higher flow rates reduced the void fraction in the FDM parts, but unexpectedly resulted in less degree of CNT alignment, which is attributed to radial flow and fusion between adjacent roads. The mechanical properties of the CNT‐PLA tensile test coupons were characterized. Inclusion of CNTs increased the Young's modulus by 30% at 5% CNT loading, but reduced the tensile strength and overall toughness of the FDM parts. Experimental data were compared against the Rule of Mixtures (RoM) model, the Halpin‐Tsai model, and the modified RoM model and were further explained by the void fraction and CNT orientation. POLYM. COMPOS., 39:E1060–E1071, 2018. © 2017 Society of Plastics Engineers

show abstract

% Crystallinity = \frac{Δ H_{f}^{normalobs}}{Δ H_{f}^{\circ}} = \frac{Δ H_{m} - Δ H_{c}}{Δ H_{f}^{\circ}}

where

Δ H_{m}, Δ H_{c}

and

Δ H_{f}^{o}

(= 93.1 J/g) are enthalpy of melting, enthalpy of crystallization and enthalpy of fusion for 100% crystalline PLA, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…where DH m ; DH c and DH o f (5 93.1 J/g) [19] are enthalpy of melting, enthalpy of crystallization and enthalpy of fusion for 100% crystalline PLA, respectively.…”

Section: Differential Scanning Calorimetry (Dsc)mentioning

confidence: 99%

The microstructure and mechanical properties of 3D printed carbon nanotube‐polylactic acid composites

et al. 2017

View full text Add to dashboard Cite

show abstract

“…This has been attributed to the displacement of the C=O bond in PLLA in response to mechanical stress leading to generation of a net dipole moment and charge [145][146][147]. PLLA has been used to fabricate films, fibres and rods with piezoelectric behaviour [148][149][150][151] and it has been observed that crystallinity and polymer orientation play key role in piezoelectric characteristic [152]. It presents an additional advantage of fabricating degradable scaffolds [153][154][155].…”

Section: Pllamentioning

confidence: 99%

Piezoelectric materials as stimulatory biomedical materials and scaffolds for bone repair

2018

View full text Add to dashboard Cite

Electrical stimulation/electrical microenvironment are known effect the process of bone regeneration by altering the cellular response and are crucial in maintaining tissue functionality. Piezoelectric materials, owing to their capability of generating charges/potentials in response to mechanical deformations, have displayed great potential for fabricating smart stimulatory scaffolds for bone tissue engineering. The growing interest of the scientific community and compelling results of the published research articles has been the motivation of this review article. This article summarizes the significant progress in the field with a focus on the fabrication aspects of piezoelectric materials. The review of both material and cellular aspects on this topic ensures that this paper appeals to both material scientists and tissue engineers.

show abstract

“…Due to its helix structure, PLLA exhibits shear piezoelectricity [ 10 ]. When PLLA is oriented and crystalline, usually as fibers or films, the chains are strained, the molecular dipoles are aligned, and a voltage difference is observed [ 11 ]. Such a structure, formulated as a piezoelectric scaffold, can be applied for piezo-stimulation and promoting cell proliferation.…”

Section: Introductionmentioning

confidence: 99%

Hydrophilicity Affecting the Enzyme-Driven Degradation of Piezoelectric Poly-l-Lactide Films

et al. 2021

View full text Add to dashboard Cite

Biocompatible and biodegradable poly-l-lactic acid (PLLA) processed into piezoelectric structures has good potential for use in medical applications, particularly for promoting cellular growth during electrostimulation. Significant advantages like closer contacts between cells and films are predicted when their surfaces are modified to make them more hydrophilic. However, there is an open question about whether the surface modification will affect the degradation process and how the films will be changed as a result. For the first time, we demonstrate that improving the polymer surface’s wettability affects the position of enzyme-driven degradation. Although it is generally considered that proteinase K degrades only the polymer surface, we observed the enzyme’s ability to induce both surface and bulk degradation. In hydrophilic films, degradation occurs at the surface, inducing surface erosion, while for hydrophobic films, it is located inside the films, inducing bulk erosion. Accordingly, changes in the structural, morphological, mechanical, thermal and wetting properties of the film resulting from degradation vary, depending on the film’s wettability. Most importantly, the degradation is gradual, so the mechanical and piezoelectric properties are retained during the degradation.

show abstract

Decoupling the effects of crystallinity and orientation on the shear piezoelectricity of polylactic acid

Cited by 44 publications

References 12 publications

The microstructure and mechanical properties of 3D printed carbon nanotube‐polylactic acid composites

The microstructure and mechanical properties of 3D printed carbon nanotube‐polylactic acid composites

Piezoelectric materials as stimulatory biomedical materials and scaffolds for bone repair

Hydrophilicity Affecting the Enzyme-Driven Degradation of Piezoelectric Poly-l-Lactide Films

Contact Info

Product

Resources

About